Quantification of Rear-End Crash Risk and Analysis of Its Influencing Factors Based on a New Surrogate Safety Measure

Table 3

Summary of variables descriptive statistics.

Independent variables (behavioral variables)
Variables	Mean	Std. Dev	Min	Max
Duration of car-following event (0.1 s)	286.66	146.44	151	1010
Mean time headway (s)	2.01	0.77	0.53	8.17
Average speed difference (m/s)	1.11	0.75	0.09	7.15
Acceleration difference ratio	0.91	0.38	0.00	4.08
Independent variables (temporal variables)
Variables	Dummy variable		Count
Day-of-week	Holiday		4200
	Workday		12705
Time-of-day	Off peak		9368
	Morning peak		3873
	Evening peak		3664
Independent variables (environmental variables)
Variables	Dummy variable		Count
Light condition	Daytime		12456
	Nighttime		4449
Weather condition	Sunny		14587
	Rainy		2318
Traffic density	High		1604
	Median		4495
	Low		10806
Dependent variables (driving risk)
Variables	Mean	Std. Dev	Min	Max
RCRI	0.0031	0.0061	0.0000	0.7736